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Calvo R, Rodriguez Mariblanca I, Pini V, Dias M, Cebrian V, Thon A, Saad A, Salvador-Matar A, Ahumada Ó, Manso Silván M, Saunders AE, Wang W, Stassinopoulos A. Novel Characterization Techniques for Multifunctional Plasmonic-Magnetic Nanoparticles in Biomedical Applications. Nanomaterials (Basel) 2023; 13:2929. [PMID: 37999283 PMCID: PMC10675523 DOI: 10.3390/nano13222929] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 11/02/2023] [Accepted: 11/08/2023] [Indexed: 11/25/2023]
Abstract
In the rapidly emerging field of biomedical applications, multifunctional nanoparticles, especially those containing magnetic and plasmonic components, have gained significant attention due to their combined properties. These hybrid systems, often composed of iron oxide and gold, provide both magnetic and optical functionalities and offer promising avenues for applications in multimodal bioimaging, hyperthermal therapies, and magnetically driven selective delivery. This paper focuses on the implementation of advanced characterization methods, comparing statistical analyses of individual multifunctional particle properties with macroscopic properties as a way of fine-tuning synthetic methodologies for their fabrication methods. Special emphasis is placed on the size-dependent properties, biocompatibility, and challenges that can arise from this versatile nanometric system. In order to ensure the quality and applicability of these particles, various novel methods for characterizing the magnetic gold particles, including the analysis of their morphology, optical response, and magnetic response, are also discussed, with the overall goal of optimizing the fabrication of this complex system and thus enhancing its potential as a preferred diagnostic agent.
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Affiliation(s)
| | | | | | - Monica Dias
- Mecwins S.A., Tres Cantos, 28760 Madrid, Spain
| | | | | | - Asis Saad
- Mecwins S.A., Tres Cantos, 28760 Madrid, Spain
| | | | | | - Miguel Manso Silván
- Departamento de Física Aplicada, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049 Madrid, Spain
| | | | - Wentao Wang
- QuidelOrtho™, San Diego, CA 92121, USA (A.S.)
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2
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Lanteri MC, Santa-Maria F, Laughhunn A, Girard YA, Picard-Maureau M, Payrat JM, Irsch J, Stassinopoulos A, Bringmann P. Inactivation of a broad spectrum of viruses and parasites by photochemical treatment of plasma and platelets using amotosalen and ultraviolet A light. Transfusion 2020; 60:1319-1331. [PMID: 32333396 PMCID: PMC7317863 DOI: 10.1111/trf.15807] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/12/2020] [Accepted: 03/13/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND The INTERCEPT Blood System pathogen reduction technology (PRT), which uses amotosalen and ultraviolet A light treatment (amotosalen/UV-PRT), inactivates pathogens in plasma and platelet components (PCs). This review summarizes data describing the inactivation efficacy of amotosalen/UVA-PRT for a broad spectrum of viruses and parasites. METHODS Twenty-five enveloped viruses, six nonenveloped viruses (NEVs), and four parasites species were evaluated for sensitivity to amotosalen/UVA-PRT. Pathogens were spiked into plasma and PC at high titers. Samples were collected before and after PRT and assessed for infectivity with cell cultures or animal models. Log reduction factors (LRFs) were defined as the difference in infectious titers before and after amotosalen/UV-PRT. RESULTS LRFs of ≥4.0 log were reported for 19 pathogens in plasma (range, ≥4.0 to ≥7.6), 28 pathogens in PC in platelet additive solution (PC-PAS; ≥4.1-≥7.8), and 14 pathogens in PC in 100% plasma (PC-100%; (≥4.3->8.4). Twenty-five enveloped viruses and two NEVs were sensitive to amotosalen/UV-PRT; LRF ranged from >2.9 to ≥7.6 in plasma, 2.4 or greater to greater than 6.9 in PC-PAS and >3.5 to >6.5 in PC-100%. Infectious titers for four parasites were reduced by >4.0 log in all PC and plasma (≥4.9 to >8.4). CONCLUSION Amotosalen/UVA-PRT demonstrated effective infectious titer reduction for a broad spectrum of viruses and parasites. This confirms the capacity of this system to reduce the risk of viral and parasitic transfusion-transmitted infections by plasma and PCs in various geographies.
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Affiliation(s)
- Marion C Lanteri
- Department of Scientific Affairs, Cerus Corporation, Concord, California, USA
| | | | - Andrew Laughhunn
- Department of Microbiology, Cerus Corporation, Concord, California, USA
| | - Yvette A Girard
- Department of Microbiology, Cerus Corporation, Concord, California, USA
| | | | - Jean-Marc Payrat
- Department of Scientific Affairs, Cerus Europe BV, Amersfoort, The Netherlands
| | - Johannes Irsch
- Department of Scientific Affairs, Cerus Europe BV, Amersfoort, The Netherlands
| | | | - Peter Bringmann
- Department of Microbiology, Cerus Corporation, Concord, California, USA
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3
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Sow C, Laughhunn A, Girard YA, Lanteri MC, Amar El Dusouqui S, Stassinopoulos A, Grellier P. Inactivation of Plasmodium falciparum in whole blood using the amustaline and glutathione pathogen reduction technology. Transfusion 2020; 60:799-805. [PMID: 32129497 PMCID: PMC7187285 DOI: 10.1111/trf.15734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/16/2020] [Accepted: 02/04/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND Risk of transfusion-transmitted (TT) malaria is mainly associated with whole blood (WB) or red blood cell (RBC) transfusion. Risk mitigation relies mostly on donor deferral while a limited number of countries perform blood testing, both negatively impacting blood availability. This study investigated the efficacy of the pathogen reduction system using amustaline and glutathione (GSH) to inactivate Plasmodium falciparum in WB. STUDY DESIGN AND METHODS WB units were spiked with ring stage P. falciparum infected RBCs. Parasite loads were measured in samples at time of infection, after 24 hours at room temperature (RT), and after a 24-hour incubation at RT post-treatment with 0.2 mM amustaline and 2 mM GSH. Serial 10-fold dilutions of the samples were inoculated to RBC cultures and maintained up to 4 weeks. Parasitemia was quantified by cytometry. RESULTS The P. falciparum viability assay has a limit of detection of a single live parasite per sample. Input parasite titer was >5.7 log10 TCID50 per mL. A 24-hour incubation at RT paused parasite development in controls, but they retained viability and infectivity when tested in culture. In contrast, no infectious parasites were detected in the amustaline/GSH-treated sample after 4 weeks of culture. CONCLUSION A robust level of P. falciparum inactivation was achieved in WB using amustaline/GSH treatment. Parasite log reduction was >5.7 log10 TCID50 per mL. Development of such a pathogen reduction system may provide an opportunity to reduce the risk of TT malaria and improve blood availability.
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Affiliation(s)
- Cissé Sow
- MCAM, UMR 7245, Muséum National dʼHistoire Naturelle, CNRSParisFrance
| | | | | | | | | | | | - Philippe Grellier
- MCAM, UMR 7245, Muséum National dʼHistoire Naturelle, CNRSParisFrance
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4
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Slichter SJ, Bailey SL, Gettinger I, Pellham E, Christoffel T, Castro G, Green JM, Stassinopoulos A. Pathogen reduction with amotosalen/UVA reduces platelet refractoriness in a dog platelet transfusion model. Vox Sang 2019; 114:595-604. [PMID: 31297836 DOI: 10.1111/vox.12818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/08/2019] [Accepted: 03/28/2019] [Indexed: 12/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Pathogen reduction of donor platelets with amotosalen/UVA has been shown to effectively inactivate pathogens and also contaminating white blood cells (WBCs). We wanted to determine whether WBC inactivation could also decrease alloimmune refractoriness to donor platelets. MATERIALS AND METHODS Platelets were prepared from a donor dog's whole blood, and the platelets were either transfused without modification [standard (STD) platelets] or treated with amotosalen/UVA under conditions modelling the amotosalen/UVA Blood System for human platelets (APR) using either 4 or 3 J/cm2 of UVA exposure. Platelets were transfused weekly from a single donor dog for 8 weeks or until the recipient dog became refractory to their donor's platelets. Antibody samples were drawn weekly and tested against the donor dog's platelets and WBCs (CD8 and B cells). RESULTS Only 1/7 (14%) dogs that received STD platelets accepted 8 weeks of donor transfusions. Following APR 4 J/cm2 donor transfusions, 3/9 (33%) recipients accepted their donor's transfusions, but only one recipient remained antibody negative. Following APR 3 J/cm2 donor transfusions, the same dose as used for human platelet transfusions, 7/10 (70%) recipients accepted their donor's transfusions, but only two remained antibody negative. CONCLUSION As a very high percentage of recipient dogs (70%) accepted APR 3 J/cm2 donor transfusions, these data suggest that preventing alloimmune platelet refractoriness may be another benefit of pathogen reduction using amotosalen/UVA.
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Affiliation(s)
- Sherrill J Slichter
- Bloodworks Northwest, Seattle, WA, USA.,University of Washington School of Medicine, Seattle, WA, USA
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5
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Sim J, Tsoi WC, Lee CK, Leung R, Lam CCK, Koontz C, Liu AY, Huang N, Benjamin RJ, Vermeij HJ, Stassinopoulos A, Corash L, Lie AKW. Transfusion of pathogen-reduced platelet components without leukoreduction. Transfusion 2019; 59:1953-1961. [PMID: 30919465 PMCID: PMC6850058 DOI: 10.1111/trf.15269] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 02/07/2019] [Accepted: 02/09/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Leukoreduction (LR) of platelet concentrate (PC) has evolved as the standard to mitigate risks of alloimmunization, clinical refractoriness, acute transfusion reactions (ATRs), and cytomegalovirus infection, but does not prevent transfusion-associated graft-versus-host disease (TA-GVHD). Amotosalen-ultraviolet A pathogen reduction (A-PR) of PC reduces risk of transfusion-transmitted infection and TA-GVHD. In vitro data indicate that A-PR effectively inactivates WBCs and infectious pathogens. STUDY DESIGN AND METHODS A sequential cohort study evaluated A-PR without LR, gamma irradiation, and bacterial screening in hematopoietic stem cell transplant (HSCT) recipients. The first cohort received conventional PC (control) processed without LR, but with gamma irradiation and bacterial screening. The second cohort received A-PR PC (test) processed without: LR, bacterial screening, or gamma irradiation. The primary efficacy outcome was the 1-hour corrected count increment. The primary safety outcome was treatment-emergent ATR. Secondary outcomes included clinical refractoriness, and 100-day status for engraftment, TA-GVHD, HSCT-GVHD, infections, and mortality. RESULTS Mean corrected count increment (× 103 ) of 33 test PC recipients was similar (18.9 ± 8.8 vs. 16.6 ± 8.4; p = 0.296) to that of 31 control PC recipients. Test recipients had a reduced, but nonsignificant, incidence of ATR (test = 9.1%, Control = 19.4%; p = 0.296). The frequencies of clinical refractoriness (0 of 33 vs. 4 of 31 patients) and refractory transfusions (6.6% vs. 19.3%) were lower in the test cohort (p = 0.05 and 0.02), respectively. No patient in either cohort had TA-GVHD. Day 100 engraftment, HSCT-GVHD, mortality, and infectious disease complications were similar between cohorts. CONCLUSIONS This study indicated that A-PR PC without LR, gamma irradiation, or bacterial screening is feasible for support of HSCT.
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Affiliation(s)
- Joycelyn Sim
- Queen Mary Hospital and University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Wai Chiu Tsoi
- Hong Kong Red Cross Blood Transfusion Service, Yau Ma Tei, Hong Kong
| | - Cheuk Kwong Lee
- Hong Kong Red Cross Blood Transfusion Service, Yau Ma Tei, Hong Kong
| | - Rock Leung
- Queen Mary Hospital and University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Clarence C K Lam
- Queen Mary Hospital and University of Hong Kong, Pok Fu Lam, Hong Kong
| | | | | | | | | | | | | | | | - Albert K W Lie
- Queen Mary Hospital and University of Hong Kong, Pok Fu Lam, Hong Kong
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Ramirez‐Arcos S, McDonald C, Deol P, Kreuger AL, Patel N, Pidcoke H, Prax M, Seltsam A, Stassinopoulos A. Bacterial safety of blood components–a congress review of the ISBT transfusion‐transmitted infectious diseases working party, bacterial subgroup. ACTA ACUST UNITED AC 2019. [DOI: 10.1111/voxs.12483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
| | | | | | | | | | | | | | - Axel Seltsam
- German Red Cross Blood Service NSTOB Springe Germany
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7
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Kleinman S, Stassinopoulos A. Transfusion-associated graft-versus-host disease reexamined: potential for improved prevention using a universally applied intervention. Transfusion 2018; 58:2545-2563. [DOI: 10.1111/trf.14930] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 07/27/2018] [Accepted: 07/29/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Steven Kleinman
- Clinical Pathology; University of British Columbia, School of Medicine; Vancouver British Columbia Canada
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Castro G, Merkel PA, Giclas HE, Gibula A, Andersen GE, Corash LM, Lin JS, Green J, Knight V, Stassinopoulos A. Amotosalen/UVA treatment inactivates T cells more effectively than the recommended gamma dose for prevention of transfusion-associated graft-versus-host disease. Transfusion 2018; 58:1506-1515. [PMID: 29607502 DOI: 10.1111/trf.14589] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare complication after transfusion of components containing viable donor T cells. Gamma irradiation with doses that stop T-cell proliferation is the predominant method to prevent TA-GVHD. Treatment with pathogen inactivation methodologies has been found to also be effective against proliferating white blood cells, including T cells. In this study, T-cell inactivation was compared, between amotosalen/ultraviolet A (UVA) treatment and gamma-irradiation (2500 cGy), using a sensitive limiting dilution assay (LDA) with an enhanced dynamic range. METHODS AND MATERIALS Matched plasma units (N = 8), contaminated with 1 × 106 peripheral blood mononuclear cells (PBMCs) per mL, were either treated with amotosalen/UVA or gamma irradiation, or retained as untreated control. Posttreatment, cells were cultured under standardized conditions. T-cell proliferation was determined by the incorporation of 3 H-thymidine and correlated with microscopic detection. RESULTS Range-finding experiments showed that after gamma irradiation (2500 cGy), significant T-cell proliferation could be observed at a 1 × 107 cell culture density, some proliferation at 1 × 106 , and none at 1 × 105 cells/well. Based on these facts, a quantitative comparison was carried out between amotosalen/UVA at the highest challenge of 1 × 107 PBMCs/well, and gamma irradiation at 1 × 106 and 1 × 105 PBMCs/well. Complete inactivation of the T cells after amotosalen/UVA treatment was observed, equivalent to greater than 6.2 log inactivation. Complete inactivation of the T cells was also observed after gamma irradiation when 1 × 105 PBMCs/well were cultured (>4.2 log inactivation). Proliferation was observed when 1 × 106 PBMCs/well were cultured (≤5.2 log inactivation) after gamma irradiation. CONCLUSION Amotosalen/UVA treatment more effectively inactivates T cells than the current standard of gamma irradiation (2500 cGy) for the prevention of TA-GVHD.
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9
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Laughhunn A, Huang YJS, Vanlandingham DL, Lanteri MC, Stassinopoulos A. Inactivation of chikungunya virus in blood components treated with amotosalen/ultraviolet A light or amustaline/glutathione. Transfusion 2018; 58:748-757. [DOI: 10.1111/trf.14442] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/03/2017] [Accepted: 11/11/2017] [Indexed: 12/19/2022]
Affiliation(s)
| | - Yan-Jang S. Huang
- Biosecurity Research Institute and Department of Diagnostic Medicine/Pathobiolgoy; Kansas State University; Manhattan Kansas
| | - Dana L. Vanlandingham
- Biosecurity Research Institute and Department of Diagnostic Medicine/Pathobiolgoy; Kansas State University; Manhattan Kansas
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10
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Aubry M, Laughhunn A, Santa Maria F, Lanteri MC, Stassinopoulos A, Musso D. Amustaline (S-303) treatment inactivates high levels of Chikungunya virus in red-blood-cell components. Vox Sang 2018; 113:232-241. [PMID: 29314033 DOI: 10.1111/vox.12626] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/16/2017] [Accepted: 11/16/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND OBJECTIVES Chikungunya virus (CHIKV) infections have been reported in all continents, and the potential risk for CHIKV transfusion-transmitted infections (TTIs) was demonstrated by the detection of CHIKV RNA-positive donations in several countries. TTIs can be reduced by pathogen inactivation (PI) of blood products. In this study, we evaluated the efficacy of amustaline and glutathione (S-303/GSH) to inactivate CHIKV in red-blood-cell concentrates (RBCs). MATERIAL AND METHODS Red-blood-cells were spiked with high level of CHIKV. Infectious titres and RNA loads were measured before and after PI treatment. Residual CHIKV infectivity was also assessed after five successive cell culture passages. RESULTS The mean CHIKV titres in RBCs before inactivation was 5·81 ± 0·18 log10 50% tissue culture infectious dose (TCID50 )/mL, and the mean viral RNA load was 10·49 ± 0·15 log10 genome equivalent (GEq)/mL. No CHIKV TCID was detected after S-303 treatment nor was replicative CHIKV particles and viral RNA present after five cell culture passages of samples obtained immediately after S-303 treatment. CONCLUSION Chikungunya virus was previously shown to be inactivated by the PI technology using amotosalen and ultraviolet A light for the treatment of plasma and platelets. This new study demonstrates that S-303/GSH can inactivate high titres of CHIKV in RBCs.
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Affiliation(s)
- M Aubry
- Pôle de recherche et de veille sur les maladies infectieuses émergentes, Institut Louis Malardé, Tahiti, French Polynesia.,Aix Marseille Univ, IRD (Dakar, Marseille, Papeete), AP-HM, IHU-Méditerranée Infection, UMR Vecteurs - Infections Tropicales et Méditerranéennes (VITROME), Marseille, France
| | | | | | | | | | - D Musso
- Pôle de recherche et de veille sur les maladies infectieuses émergentes, Institut Louis Malardé, Tahiti, French Polynesia.,Aix Marseille Univ, IRD (Dakar, Marseille, Papeete), AP-HM, IHU-Méditerranée Infection, UMR Vecteurs - Infections Tropicales et Méditerranéennes (VITROME), Marseille, France
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11
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Aubry M, Laughhunn A, Santa Maria F, Lanteri MC, Stassinopoulos A, Musso D. Pathogen inactivation of Dengue virus in red blood cells using amustaline and glutathione. Transfusion 2017; 57:2888-2896. [DOI: 10.1111/trf.14318] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/29/2017] [Accepted: 08/02/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Maite Aubry
- Pôle de Recherche et de Veille sur les Maladies Infectieuses Émergentes, Institut Louis Malardé; Tahiti, Polynésie Française
| | | | | | - Marion C. Lanteri
- Scientific Affairs Department; Cerus Corporation; Concord California
| | | | - Didier Musso
- Pôle de Recherche et de Veille sur les Maladies Infectieuses Émergentes, Institut Louis Malardé; Tahiti, Polynésie Française
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12
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Tonnetti L, Laughhunn A, Thorp AM, Vasilyeva I, Dupuis K, Stassinopoulos A, Stramer SL. Inactivation of Babesia microti in red blood cells and platelet concentrates. Transfusion 2017; 57:2404-2412. [PMID: 28872685 DOI: 10.1111/trf.14280] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 06/12/2017] [Accepted: 07/05/2017] [Indexed: 01/30/2023]
Abstract
BACKGROUND With an increasing number of recognized transfusion-transmitted (TT) babesiosis cases, Babesia microti is the most frequently TT parasite in the United States. We evaluated the inactivation of B. microti in red blood cells (RBCs) prepared in Optisol (AS-5) using amustaline and glutathione (GSH) and in platelet components (PCs) in 100% plasma using amotosalen and low-energy ultraviolet A (UVA) light. STUDY DESIGN AND METHODS Individual RBCs and apheresis PCs were spiked with B. microti-infected hamster RBCs (iRBCs) to a final concentration of 106 iRBCs/mL and treated with the respective inactivation systems according to the manufacturer's instruction. Samples were collected before (control) and after (test) each treatment. Dilutions of the control samples to 10-6 were inoculated into hamsters, while the test samples were inoculated neat or at 10-1 dilution. At 3 and 5 weeks postinoculation, hamsters were evaluated for B. microti infection by microscopic observation of blood smears and 50% infectivity titers (ID50 ) were determined. Log reduction was calculated as control log ID50 minus test log ID50 . RESULTS Parasitemia was detected in hamsters injected with as low as 100,000-fold diluted control samples, while no parasites were detectable in the blood smears of any hamsters receiving neat test samples. Mean log reduction was more than 5 log/mL by amustaline/GSH for RBCs and more than 4.5 log/mL by amotosalen/UVA for PCs. CONCLUSION B. microti was inactivated to the limit of detection in RBCs and PCs after the respective inactivation treatment. Complete inactivation of B. microti was achieved in this animal infectivity model, and pathogen reduction treatment inhibited transmission of infection.
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Affiliation(s)
- Laura Tonnetti
- Scientific Affairs, American Red Cross Holland Laboratory, Rockville, Maryland
| | | | - Aaron M Thorp
- Scientific Affairs, American Red Cross Holland Laboratory, Rockville, Maryland
| | - Irina Vasilyeva
- Scientific Affairs, American Red Cross Holland Laboratory, Rockville, Maryland
| | | | | | - Susan L Stramer
- Scientific Affairs, American Red Cross Holland Laboratory, Rockville, Maryland
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13
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Merkel PA, Giclas HE, Payrat JM, Knight V, Castro G, Stassinopoulos A. Inactivation des lymphocytes T par traitement photochimique avec amotosalen. Transfus Clin Biol 2017. [DOI: 10.1016/j.tracli.2017.06.279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Santa Maria F, Laughhunn A, Lanteri MC, Aubry M, Musso D, Stassinopoulos A. Inactivation of Zika virus in platelet components using amotosalen and ultraviolet A illumination. Transfusion 2017; 57:2016-2025. [DOI: 10.1111/trf.14161] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 04/06/2017] [Accepted: 04/07/2017] [Indexed: 12/16/2022]
Affiliation(s)
| | | | | | - Maite Aubry
- Pôle de Recherche et de Veille sur les Maladies Infectieuses Émergentes, Institut Louis Malardé; Tahiti Polynésie Française
| | - Didier Musso
- Pôle de Recherche et de Veille sur les Maladies Infectieuses Émergentes, Institut Louis Malardé; Tahiti Polynésie Française
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15
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Laughhunn A, Santa Maria F, Broult J, Lanteri MC, Stassinopoulos A, Musso D, Aubry M. Amustaline (S-303) treatment inactivates high levels of Zika virus in red blood cell components. Transfusion 2017; 57:779-789. [DOI: 10.1111/trf.13993] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/01/2016] [Accepted: 12/04/2016] [Indexed: 12/16/2022]
Affiliation(s)
| | | | - Julien Broult
- Centre de Transfusion Sanguine de la Polynésie Française, Hôpital du Taaone
| | | | | | - Didier Musso
- Pôle de Recherche et de Veille sur les Maladies Infectieuses Émergentes, Institut Louis Malardé; Tahiti Polynésie Française
| | - Maite Aubry
- Pôle de Recherche et de Veille sur les Maladies Infectieuses Émergentes, Institut Louis Malardé; Tahiti Polynésie Française
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16
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Payrat JM, Santa Maria F, Laughhunn A, Lenhoff R, Stassinopoulos A. Inactivation efficace du virus Zika par formation d’adduits aux acides nucléiques. Transfus Clin Biol 2016. [DOI: 10.1016/j.tracli.2016.08.116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Payrat JM, Patel N, Goldbeck K, Lenhoff R, Stassinopoulos A. Inactivation robuste de Klebsiella pneumoniae, indépendamment de la sensibilité génétique aux antibiotiques par traitement photochimique de plaquettes en solution PAS-3. Transfus Clin Biol 2016. [DOI: 10.1016/j.tracli.2016.08.113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Payrat JM, Castro G, Stassinopoulos A. Inactivation efficace des cellules T avec amustaline/GSH dans les concentrés de globules rouges par la méthode de dilution limite en fluorescence (LDA). Transfus Clin Biol 2016. [DOI: 10.1016/j.tracli.2016.08.115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Laughhunn A, Grellier P, Sow C, Stassinopoulos A. Inactivation du Plasmodium falciparum avec amotosalen/UVA dans des concentrés de plaquettes suspendus en 100 % plasma. Transfus Clin Biol 2016. [DOI: 10.1016/j.tracli.2016.08.117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Payrat JM, Santa Maria F, Laughhunn A, Lenhoff R, Stassinopoulos A. Le Calicivirus félin non enveloppé est inactivé efficacement par l’amustaline/GSH dans les concentrés de globules rouges. Transfus Clin Biol 2016. [DOI: 10.1016/j.tracli.2016.08.112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wagner SJ, Benjamin RJ, Hapip CA, Kaelber NS, Turgeon AM, Skripchenko A, Stassinopoulos A. Investigation of bacterial inactivation in apheresis platelets with 24 or 30 hours between inoculation and inactivation. Vox Sang 2016; 111:226-234. [DOI: 10.1111/vox.12410] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/09/2016] [Accepted: 03/22/2016] [Indexed: 02/06/2023]
Affiliation(s)
- S. J. Wagner
- Transfusion Innovation Department American Red Cross Holland Laboratory Rockville MD USA
| | | | - C. A. Hapip
- Transfusion Innovation Department American Red Cross Holland Laboratory Rockville MD USA
| | - N. S. Kaelber
- Transfusion Innovation Department American Red Cross Holland Laboratory Rockville MD USA
| | - A. M. Turgeon
- Transfusion Innovation Department American Red Cross Holland Laboratory Rockville MD USA
| | - A. Skripchenko
- Transfusion Innovation Department American Red Cross Holland Laboratory Rockville MD USA
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Knutson F, Osselaer J, Pierelli L, Lozano M, Cid J, Tardivel R, Garraud O, Hervig T, Domanovic D, Cukjati M, Gudmundson S, Hjalmarsdottir IB, Castrillo A, Gonzalez R, Brihante D, Santos M, Schlenke P, Elliott A, Lin JS, Tappe D, Stassinopoulos A, Green J, Corash L. A prospective, active haemovigilance study with combined cohort analysis of 19,175 transfusions of platelet components prepared with amotosalen-UVA photochemical treatment. Vox Sang 2015; 109:343-52. [PMID: 25981525 PMCID: PMC4690512 DOI: 10.1111/vox.12287] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 03/24/2015] [Accepted: 03/27/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVES A photochemical treatment process (PCT) utilizing amotosalen and UVA light (INTERCEPT(™) Blood System) has been developed for inactivation of viruses, bacteria, parasites and leucocytes that can contaminate blood components intended for transfusion. The objective of this study was to further characterize the safety profile of INTERCEPT-treated platelet components (PCT-PLT) administered across a broad patient population. MATERIALS AND METHODS This open-label, observational haemovigilance programme of PCT-PLT transfusions was conducted in 21 centres in 11 countries. All transfusions were monitored for adverse events within 24 h post-transfusion and for serious adverse events (SAEs) up to 7 days post-transfusion. All adverse events were assessed for severity (Grade 0-4), and causal relationship to PCT-PLT transfusion. RESULTS Over the course of 7 years in the study centres, 4067 patients received 19,175 PCT-PLT transfusions. Adverse events were infrequent, and most were of Grade 1 severity. On a per-transfusion basis, 123 (0.6%) were classified an acute transfusion reaction (ATR) defined as an adverse event related to the transfusion. Among these ATRs, the most common were chills (77, 0.4%) and urticaria (41, 0.2%). Fourteen SAEs were reported, of which 2 were attributed to platelet transfusion (<0.1%). No case of transfusion-related acute lung injury, transfusion-associated graft-versus-host disease, transfusion-transmitted infection or death was attributed to the transfusion of PCT-PLT. CONCLUSION This longitudinal haemovigilance safety programme to monitor PCT-PLT transfusions demonstrated a low rate of ATRs, and a safety profile consistent with that previously reported for conventional platelet components.
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Affiliation(s)
- F Knutson
- Department of Immunology, Genetics, and Pathology, Uppsala University, Uppsala, Sweden
| | - J Osselaer
- Cliniques Universitaires de Mont Godinne, Universite Catholique de Louvain, Yvoir, Belgium
| | - L Pierelli
- Department of Experimental Medicine, Sapienza University of Roma, Rome, Italy
| | - M Lozano
- Department of Hemotherapy and Hemostasis, CDB, IDIBAPS, Hospital Clinic, Barcelona, Spain
| | - J Cid
- Department of Hemotherapy and Hemostasis, CDB, IDIBAPS, Hospital Clinic, Barcelona, Spain
| | | | - O Garraud
- EFS Auvergne Loire, St. Etienne, France
| | - T Hervig
- Department of Immunology and Transfusion Medicine, University of Bergen, Bergen, Norway
| | - D Domanovic
- Blood Transfusion Centre of Slovenia, Ljubljana, Slovenia
| | - M Cukjati
- Blood Transfusion Centre of Slovenia, Ljubljana, Slovenia
| | - S Gudmundson
- Blood Bank, National University Hospital, Reykjavik, Iceland
| | | | - A Castrillo
- Transfusion Centre of Galicia, Santiago de Compostela, Spain
| | - R Gonzalez
- Transfusion Centre of Galicia, Santiago de Compostela, Spain
| | - D Brihante
- Servico de Imuno-Hemoterapia, Instituto Portugues de Oncologia de Lisboa, Lisbon, Portugal
| | - M Santos
- Servico de Imuno-Hemoterapia, Instituto Portugues de Oncologia de Lisboa, Lisbon, Portugal
| | - P Schlenke
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria
| | | | - J-S Lin
- Cerus Corporation, Concord, CA, USA
| | - D Tappe
- Cerus Corporation, Concord, CA, USA
| | | | - J Green
- Cerus Corporation, Concord, CA, USA
| | - L Corash
- Cerus Corporation, Concord, CA, USA
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Bakkour S, Chafets DM, Wen L, Dupuis K, Castro G, Green JM, Stassinopoulos A, Busch MP, Lee T. Assessment of nucleic acid modification induced by amotosalen and ultraviolet A light treatment of platelets and plasma using real‐time polymerase chain reaction amplification of variable length fragments of mitochondrial DNA. Transfusion 2015; 56:410-20. [DOI: 10.1111/trf.13360] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 07/22/2015] [Accepted: 08/31/2015] [Indexed: 12/16/2022]
Affiliation(s)
- Sonia Bakkour
- Blood Systems Research InstituteSan Francisco California
| | | | - Li Wen
- Blood Systems Research InstituteSan Francisco California
| | | | | | | | | | - Michael P. Busch
- Blood Systems Research InstituteSan Francisco California
- University of California San FranciscoSan Francisco California
| | - Tzong‐Hae Lee
- Blood Systems Research InstituteSan Francisco California
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24
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Kleinman S, Stassinopoulos A. Risks associated with red blood cell transfusions: potential benefits from application of pathogen inactivation. Transfusion 2015; 55:2983-3000. [PMID: 26303806 PMCID: PMC7169855 DOI: 10.1111/trf.13259] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 06/02/2015] [Accepted: 06/22/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND Red blood cell (RBC) transfusion risks could be reduced if a robust technology for pathogen inactivation of RBC (PI-RBCs) were to be approved. MATERIALS AND METHODS Estimates of per-unit and per-patient aggregate infectious risks for conventional RBCs were calculated; the latter used patient diagnosis as a determinant of estimated lifetime exposure to RBC units. Existing in vitro data for the two technologies under development for producing PI-RBCs and the status of current clinical trials are reviewed. RESULTS Minimum and maximum per-unit risk were calculated as 0.0003% (1 in 323,000) and 0.12% (1 in 831), respectively. The minimum estimate is for known lower-risk pathogens while the maximal estimate also includes an emerging infectious agent (EIA) and endemic area Babesia risk. Minimum and maximum per-patient lifetime risks by diagnosis grouping were estimated as 1.5 and 3.3%, respectively, for stem cell transplantation (which includes additional risk for cytomegalovirus transmission); 1.2 and 3.7%, respectively, for myelodysplastic syndrome; and 0.2 and 44%, respectively, for hemoglobinopathy. DISCUSSION There is potential for PI technologies to reduce infectious RBC risk and to provide additional benefits (e.g., prevention of transfusion-associated graft-versus-host disease and possible reduction of alloimmunization) due to white blood cell inactivation. PI-RBCs should be viewed in the context of having a fully PI-treated blood supply, enabling a blood safety paradigm shift from reactive to proactive. Providing insurance against new EIAs. Further, when approved, the use of PI for all components may catalyze operational changes in blood donor screening, laboratory testing, and component manufacturing.
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Affiliation(s)
- Steve Kleinman
- University of British Columbia, Victoria, British Columbia, Canada
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McCullough J, Goldfinger D, Gorlin J, Riley WJ, Sandhu H, Stowell C, Ward D, Clay M, Pulkrabek S, Chrebtow V, Stassinopoulos A. Cost implications of implementation of pathogen-inactivated platelets. Transfusion 2015; 55:2312-20. [PMID: 25989465 PMCID: PMC4691315 DOI: 10.1111/trf.13149] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 03/09/2015] [Accepted: 03/18/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND Pathogen inactivation (PI) is a new approach to blood safety that may introduce additional costs. This study identifies costs that could be eliminated, thereby mitigating the financial impact. STUDY DESIGN AND METHODS Cost information was obtained from five institutions on tests and procedures (e.g., irradiation) currently performed, that could be eliminated. The impact of increased platelet (PLT) availability due to fewer testing losses, earlier entry into inventory, and fewer outdates with a 7-day shelf life were also estimated. Additional estimates include costs associated with managing 1) special requests and 2) test results, 3) quality control and proficiency testing, 4) equipment acquisition and maintenance, 5) replacement of units lost to positive tests, 6) seasonal or geographic testing, and 7) health department interactions. RESULTS All costs are mean values per apheresis PLT unit in USD ($/unit). The estimated test costs that could be eliminated are $71.76/unit and a decrease in transfusion reactions corresponds to $2.70/unit. Avoiding new tests (e.g., Babesia and dengue) amounts to $41.80/unit. Elimination of irradiation saves $8.50/unit, while decreased outdating with 7-day storage can be amortized to $16.89/unit. Total potential costs saved with PI is $141.65/unit. Costs are influenced by a variety of factors specific to institutions such as testing practices and the location in which such costs are incurred and careful analysis should be performed. Additional benefits, not quantified, include retention of some currently deferred donors and scheduling flexibility due to 7-day storage. CONCLUSIONS While PI implementation will result in additional costs, there are also potential offsetting cost reductions, especially after 7-day storage licensing.
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Affiliation(s)
- Jeffrey McCullough
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota
| | - Dennis Goldfinger
- Department of Laboratory Medicine and Pathology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Jed Gorlin
- Memorial Blood Centers/Innovative Blood Resources, St Paul, Minnesota
| | - William J Riley
- College of the Science of Health Care Delivery, Arizona State University, Tempe, Arizona
| | - Harpreet Sandhu
- Stanford Blood Center, Stanford University School of Medicine, Stanford, California
| | - Christopher Stowell
- Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Dawn Ward
- Department of Laboratory Medicine and Pathology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Mary Clay
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota
| | - Shelley Pulkrabek
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota
| | - Vera Chrebtow
- Global Scientific Affairs, Cerus Corporation, Concord, California
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Kleinman S, Reed W, Stassinopoulos A. A patient-oriented risk-benefit analysis of pathogen-inactivated blood components: application to apheresis platelets in the United States. Transfusion 2012; 53:1603-18. [DOI: 10.1111/j.1537-2995.2012.03928.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Revised: 08/24/2012] [Accepted: 08/25/2012] [Indexed: 12/21/2022]
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28
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29
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Cappillino PJ, Tarves PC, Rowe GT, Lewis AJ, Harvey M, Rogge C, Stassinopoulos A, Lo W, Armstrong WH, Caradonna JP. Synthesis and characterization of a family of binuclear non-heme iron monooxygenase model compounds: Evidence for a “phenolate/amide carbonyl (PAC) shift” upon oxidation. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2008.09.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
The objective of this study was to examine the effects of polyethylene glycol (PEG) treated red blood cells (RBCs) on the microcirculation in a hamster back skin window chamber model. Donor hamster RBCs were PEGylated through an incubation with an activated PEG solution, washed, resuspended, and infused through a 10% volume top loading procedure into the carotid artery in an awake Syrian Golden hamster. Eight hamster groups were treated with activated PEG different sizes and concentrations: 0.05 mM-5 kDa PEG, 0.5 mM-5 kDa PEG, 1.1 mM-5 kDa PEG, 2.2 mM-5 kDa PEG, 22 mM-5 kDa PEG, 0.05 mM-20 kDa PEG, 0.5 mM-20 kDa PEG, and 5 mM-20 kDa PEG. Non-treated RBCs were used as control. The microvascular bed under observation was videotaped 30 min before the infusion and followed for 30 min post infusion. The diameter of individual blood vessels and blood flow velocities in selected vessels was measured. Hematocrit and hemoglobin concentration were recorded before infusion and at the end of experiment. Tissue pO(2) was also monitored. Results showed the hamsters tolerated the PEGylated RBCs without apparent ill effects. No significant changes were recorded for the hematocrit, the hemoglobin concentration, the blood vessel diameters, blood flow velocities, and the interstitial partial oxygen pressure (pO(2)) before, during, and after the injections of PEG-RBCs (P > 0.05). Unlike most hemoglobin-based oxygen carrying compounds, which can cause vasoconstriction, the PEGylated RBCs did not produce any measurable vasoactivity. Together with the absence of rouleaux formation and the fact that PEG molecules can mask the surface antigens on RBCs, PEGylation appeared promising as a circulation enhancement treatment.
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Affiliation(s)
- Peter C Y Chen
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093-0412, USA.
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31
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Sawyer L, Hanson D, Castro G, Luckett W, Dubensky TW, Stassinopoulos A. Inactivation of parvovirus B19 in human platelet concentrates by treatment with amotosalen and ultraviolet A illumination. Transfusion 2007; 47:1062-70. [PMID: 17524098 DOI: 10.1111/j.1537-2995.2007.01237.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The human erythrovirus B19 (B19) is a small (18- to 26-nm) nonenveloped virus with a single-stranded DNA genome of 5.6 kb. B19 is clinically significant and is also generally resistant to pathogen inactivation methods. Photochemical treatment (PCT) with amotosalen and ultraviolet A (UVA) inactivates viruses, bacteria, and protozoa in platelets (PLTs) and plasma prepared for transfusion. In this study, the capacity of PCT to inactivate B19 in human PLT concentrates was evaluated. STUDY DESIGN AND METHODS B19 inactivation was measured by a novel enzyme-linked immunosorbent spot (ELISPOT) erythroid progenitor cell infectivity assay and by inhibition of long-range (up to 4.3 kb) polymerase chain reaction (PCR), under conditions where the whole coding region of the viral genome was amplified. B19-infected plasma was used to test whether incubation of amotosalen with virus before PCT enhanced inactivation compared to immediate PCT. RESULTS Inactivation of up to 5.8 log of B19 as measured by the infectivity assay, or up to 6 logs as measured by PCR inhibition can be achieved under non-limiting conditions. Inactivation efficacy was found to increase with incubation prior to UVA illumination. Without incubation prior to illumination 2.1 +0.4 log was inactivated as determined by infectivity assay. When measured by PCR inhibition, inactivation varied inversely with amplicon size. When primers that spanned the entire coding region of the B19 genome were used, maximum inhibition of PCR amplification was demonstrated. CONCLUSION Under defined conditions, PCT with amotosalen combined with UVA light can be used to inactivate B19, a clinically significant virus that can be transmitted through blood transfusion, and heretofore has been demonstrated to be refractory to inactivation.
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Allain JP, Hsu J, Pranmeth M, Hanson D, Stassinopoulos A, Fischetti L, Corash L, Lin L. Quantification of viral inactivation by photochemical treatment with amotosalen and UV A light, using a novel polymerase chain reaction inhibition method with preamplification. J Infect Dis 2006; 194:1737-44. [PMID: 17109347 PMCID: PMC7110026 DOI: 10.1086/509260] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 08/04/2006] [Indexed: 11/23/2022] Open
Abstract
Background. In evaluating a photochemical treatment process for inactivating parvovirus B19, there lacked simple culture methods to measure infectivity. The recently developed enzyme‐linked immunospot (ELISpot) infectivity assay uses late‐stage erythropoietic progenitor cells and is labor intensive and time consuming. We evaluated a novel, efficient polymerase chain reaction (PCR) inhibition assay and examined correlations with reductions in infectivity. Methods. Contaminated plasma was treated with 150 μmol/L amotosalen and 3 J/cm2 ultraviolet A light and then tested for DNA modification using conventional PCR inhibition and a novel preamplification approach. The novel assay subjected the samples to preamplification cycles using long‐template PCR, followed by quantitative PCR (QPCR) inhibition detection. Both approaches were tested for correlations with reductions in viral infectivity by comparing ELISpot assay results of identical samples. Results. The B19 preamplification inhibition assay showed detection ranges of 2–2.5 log and demonstrated quantitative correlation with up to a 5.8‐log reduction in viral infectivity in ELISpot results. Conventional PCR detected a >5 log reduction in amplification, correlated with a 4.4‐log reduction in viral infectivity. A range of 4‐log inhibition of hepatitis B virus DNA amplification was also achieved. Conclusions. The results demonstrated that a novel preamplification QPCR assay is a useful tool for predicting reductions in infectivity after photochemical treatment. This assay was extended to show utility in circumstances where practical in vitro assays are unavailable for the determination of the efficacy of pathogen inactivation.
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Brockstedt DG, Bahjat KS, Giedlin MA, Liu W, Leong M, Luckett W, Gao Y, Schnupf P, Kapadia D, Castro G, Lim JYH, Sampson-Johannes A, Herskovits AA, Stassinopoulos A, Bouwer HGA, Hearst JE, Portnoy DA, Cook DN, Dubensky TW. Killed but metabolically active microbes: a new vaccine paradigm for eliciting effector T-cell responses and protective immunity. Nat Med 2005; 11:853-60. [PMID: 16041382 DOI: 10.1038/nm1276] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Accepted: 06/22/2005] [Indexed: 01/28/2023]
Abstract
We developed a new class of vaccines, based on killed but metabolically active (KBMA) bacteria, that simultaneously takes advantage of the potency of live vaccines and the safety of killed vaccines. We removed genes required for nucleotide excision repair (uvrAB), rendering microbial-based vaccines exquisitely sensitive to photochemical inactivation with psoralen and long-wavelength ultraviolet light. Colony formation of the nucleotide excision repair mutants was blocked by infrequent, randomly distributed psoralen crosslinks, but the bacterial population was able to express its genes, synthesize and secrete proteins. Using the intracellular pathogen Listeria monocytogenes as a model platform, recombinant psoralen-inactivated Lm DeltauvrAB vaccines induced potent CD4(+) and CD8(+) T-cell responses and protected mice against virus challenge in an infectious disease model and provided therapeutic benefit in a mouse cancer model. Microbial KBMA vaccines used either as a recombinant vaccine platform or as a modified form of the pathogen itself may have broad use for the treatment of infectious disease and cancer.
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Affiliation(s)
- D G Brockstedt
- Cerus Corporation, 2411 Stanwell Drive, Concord, California 94520, USA
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Stassinopoulos A, Schulte G, Papaefthymiou GC, Caradonna JP. Synthesis, structure, and electronic characterization of reactive diiron(II) 1,2-bis(2-hydroxybenzamido)benzene complexes as models for methane monooxygenase. J Am Chem Soc 2002. [DOI: 10.1021/ja00023a016] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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35
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Stassinopoulos A, Caradonna JP. A binuclear non-heme iron oxo-transfer analog reaction system: observations and biological implications. J Am Chem Soc 2002. [DOI: 10.1021/ja00175a058] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Gao X, Stassinopoulos A, Ji J, Kwon Y, Bare S, Goldberg IH. Induced formation of a DNA bulge structure by a molecular wedge ligand-postactivated neocarzinostatin chromophore. Biochemistry 2002; 41:5131-43. [PMID: 11955061 DOI: 10.1021/bi012112o] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Our previous structure elucidation of the complexes of DNA and postactivated neocarzinostatin chromophore (NCS-chrom) compounds revealed two distinctly different binding modes of this antitumor molecule. A thorough understanding of these results will provide the molecular basis for the binding and DNA chain cleavage properties of NCS-chrom. NCSi-gb is one of the postactivated mimics of NCS-chrom which is formed under thiol-free conditions and is able to bind to DNA. This report describes the structure refinement of the NCSi-gb-bulge-DNA complex [Stassinopoulos, A., Jie, J., Gao, X., and Goldberg, I. H. (1996) Science 272, 1943-1946] and the NMR characterization of the free bulge-DNA and free NCSi-gb. These results reveal that the formation of the complex involves conformational changes in both the DNA and the ligand molecule. Of mechanistic importance for the NCS-chrom-DNA interaction, the two ring systems of the drug are brought closer to each other in the complex. This conformation correlates well with the previously observed marked enhancement of the formation of a DNA bulge cleaving species in the presence of bulge-DNA sequences, due to the promotion of the intramolecular radical quenching of the activated NCS-chrom. Interestingly, the binding of NCSi-gb promotes the formation of a bulge binding pocket; this was not found in the unbound DNA. NCS-chrom is unique among the enediyne antibiotics in its ability to undergo two different mechanisms of activation to form two different DNA binding and cleaving species. The two corresponding DNA complexes are compared. One, the bulge-DNA binder NCSi-gb, involves the major groove, and the second, the duplex binder NCSi-glu which is generated by glutathione-induced activation, involves the minor groove. Since the two NCS-chrom-related ligand molecules contain some common chemical structural elements, such as the carbohydrate ring, the striking differences in their DNA recognition and chain cleavage specificity provide insights into the fundamental principles of DNA recognition and ligand design.
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Affiliation(s)
- Xiaolian Gao
- Department of Chemistry, University of Houston, 4800 Calhoun Street, Houston, Texas 77204-5003, USA.
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37
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Weimer RM, Creighton CX, Stassinopoulos A, Youderian P, Hartzell PL. A chaperone in the HSP70 family controls production of extracellular fibrils in Myxococcus xanthus. J Bacteriol 1998; 180:5357-68. [PMID: 9765567 PMCID: PMC107584 DOI: 10.1128/jb.180.20.5357-5368.1998] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/1998] [Accepted: 08/05/1998] [Indexed: 11/20/2022] Open
Abstract
Three independent Tn5-lac insertions in the S1 locus of Myxococcus xanthus inactivate the sglK gene, which is nonessential for growth but required for social motility and multicellular development. The sequence of sglK reveals that it encodes a homologue of the chaperone HSP70 (DnaK). The sglK gene is cotranscribed with the upstream grpS gene, which encodes a GrpE homologue. Unlike sglK, grpS is not required for social motility or development. Wild-type M. xanthus is encased in extracellular polysaccharide filaments associated with the multimeric fibrillin protein. Mutations in sglK inhibit cell cohesion, the binding of Congo red, and the synthesis or secretion of fibrillin, indicating that sglK mutants do not make fibrils. The fibR gene, located immediately upstream of the grpS-sglK operon, encodes a product which is predicted to have a sequence similar to those of the repressors of alginate biosynthesis in Pseudomonas aeruginosa and Pseudomonas putida. Inactivation of fibR leads to the overproduction of fibrillin, suggesting that M. xanthus fibril production and Pseudomonas alginate production are regulated in analogous ways. M. xanthus and Pseudomonas exopolysaccharides may play similar roles in a mechanism of social motility conserved in these gram-negative bacteria.
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Affiliation(s)
- R M Weimer
- Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844-3052, USA
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Mukerjee S, Stassinopoulos A, Caradonna JP. Iodosylbenzene Oxidation of Alkanes, Alkenes, and Sulfides Catalyzed by Binuclear Non-heme Iron Systems: Comparison of Non-heme Iron Versus Heme Iron Oxidation Pathways. J Am Chem Soc 1997. [DOI: 10.1021/ja9709482] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Subhasish Mukerjee
- Department of Chemistry, Kline Laboratory Yale University, P.O. Box 208107 New Haven, Connecticut 06520-8107
| | - Adonis Stassinopoulos
- Department of Chemistry, Kline Laboratory Yale University, P.O. Box 208107 New Haven, Connecticut 06520-8107
| | - John P. Caradonna
- Department of Chemistry, Kline Laboratory Yale University, P.O. Box 208107 New Haven, Connecticut 06520-8107
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Abstract
Nucleic acid bulges have been implicated in a number of biological processes and are specific cleavage targets for the enediyne antitumor antibiotic neocarzinostatin chromophore in a base-catalyzed, radical-mediated reaction. The solution structure of the complex between an analog of the bulge-specific cleaving species and an oligodeoxynucleotide containing a two-base bulge was elucidated by nuclear magnetic resonance. An unusual binding mode involves major groove recognition by the drug carbohydrate unit and tight fitting of the wedge-shaped drug in the triangular prism pocket formed by the two looped-out bulge bases and the neighboring base pairs. The two drug rings mimic helical DNA bases, complementing the bent DNA structure. The putative abstracting drug radical is 2.2 +/- 0.1 angstroms from the pro-S H5' of the target bulge nucleotide. This structure clarifies the mechanism of bulge recognition and cleavage by a drug and provides insight into the design of bulge-specific nucleic acid binding molecules.
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Affiliation(s)
- A Stassinopoulos
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Stassinopoulos A, Goldberg IH. Probing the structure of long single-stranded DNA fragments with neocarzinostatin chromophore. Extension of the base-catalyzed bulge-specific reaction. Biochemistry 1995; 34:15359-74. [PMID: 7578152 DOI: 10.1021/bi00046a045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The base-catalyzed (bc) thiol-independent cleavage reaction of neocarzinostatin chromophore (NCS chrom) has been characterized with long single-stranded (ss) DNA in order to use this reaction as a selective probe for the tertiary structure of naturally occurring ss nucleic acids. The ss circular phi chi 174 phage and M13mp18 phage DNAs (approximately 5000 and 7500 bases, respectively) were shown to be bc NCS chrom reaction substrates, exhibiting the expected pH dependence. The ss DNA fragments (150-450 bases) were cleaved at six major sites; the lesions occurred at T-rich non-double-stranded sequences, as predicted from comparison with the minimal energy secondary structures. These sites exhibited the expected pH and drug: DNA ratio dependence shown to be required for this reaction. Optimization of the shortest sequence, which gave the highest cleavage yield, identified the minimal sequence requirements for the site (19-mer of the sequence 3'TACTGAGTCTCCTTTTGTA5', attacked residue in bold). Folding pattern analysis predicted that the oligonucleotide contained a two-base bulge at the cleavage site; this result was consistent with the observation that removing features which destabilize the bulged structure increased the cleavage yield. Furthermore, the derived 19-mer was shown to generate maximal amounts of the final drug product of the bc DNA cleavage reaction. Reaction of an RNA 339-mer containing the same sequence as one of the long ss DNA fragments showed it not to be a substrate for the bc reaction, while similar results were obtained for the RNA analog of shorter oligodeoxyribonucleotides identified in this and earlier studies. Through a combination of thermodynamic and kinetic assays, the observed difference in reactivity was shown to be the result of the low binding of the cleaving species to RNA.
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Affiliation(s)
- A Stassinopoulos
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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42
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Stassinopoulos A, Goldberg IH. Binding and cleavage characteristics of the complexes formed between the neocarzinostatin chromophore and single site containing oligonucleotides. Bioorg Med Chem 1995; 3:713-21. [PMID: 7582949 DOI: 10.1016/0968-0896(95)00062-l] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
It is shown by fluorescence spectroscopy that the post-activated form of neocarzinostatin chromophore (NCSi-glu) can form stable complexes with single-site oligonucleotides (SSOs) featuring sequences known to be involved in double stranded (AGC.GCT, AGT.ACT, AGA.TCT, ACA.TGT) or single stranded (AGG.CCT) cleavage (attacked residues in bold). Furthermore, the same SSOs form cleavage productive complexes with native neocarzinostatin chromophore (NCS chrom) over a similar concentration range. The productive complexes yield damage similar to that observed if the same sequence is part of a longer DNA piece. Previously identified double stranded site sequences ATT.AAT and TAT.ATA are shown to contain overlapping attack sites. Binding order preference derived from fluorescence quenching experiments for NCSi-glu is consistent with constants derived by quantitative cleavage affinity binding experiments with NCS chrom. This confirms the similarity in interactions between the NCSi-glu and NCS chrom and justifies the use of NCSi-glu as a stable analog of NCS chrom.
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Affiliation(s)
- A Stassinopoulos
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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Gao X, Stassinopoulos A, Gu J, Goldberg IH. NMR studies of the post-activated neocarzinostatin chromophore-DNA complex. Conformational changes induced in drug and DNA. Bioorg Med Chem 1995; 3:795-809. [PMID: 7582957 DOI: 10.1016/0968-0896(95)00063-m] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The glutathione post-activated neocarzinostatin chromophore (NCSi-glu)-DNA complex was studied in detail by 2-D NMR spectroscopy. The complex is a model for understanding the sequence specific cleavage of DNA by the native neocarzinostatin chromophore (NCS chrom), a highly potent enediyne antitumor agent. NMR spectral analysis is presented for the free NCSi-glu, the free DNA duplex and the NCSi-glu-DNA complex. In addition to the previously reported structural details of the complex (Gao, X.; Stassinopoulos, A.; Rice, J. S.; Goldberg, I. H. Biochemistry 1995, 34, 40), we demonstrate that the binding of NCSi-glu in minor groove results in a patch of negatively charged surface covering the otherwise relatively neutral minor groove. The formation of the complex is largely driven by hydrophobic forces and the solvation of the polar surface of the complex. Comparison of the conformations of NCSi-glu and DNA duplex in their free and bound form reveals an induced mutual fit of DNA and NCSi-glu upon complex formation. The reduced NCS chrom represents a DNA binding motif for sequence specific recognition of DNA via intercalation and minor groove interactions.
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Affiliation(s)
- X Gao
- Department of Chemistry, University of Houston, TX 77204-5641, USA
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Yang CF, Stassinopoulos A, Goldberg IH. Specific binding of the biradical analog of neocarzinostatin chromophore to bulged DNA: implications for thiol-independent cleavage. Biochemistry 1995; 34:2267-75. [PMID: 7857937 DOI: 10.1021/bi00007a022] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The enediyne anticancer antibiotic neocarzinostatin chromophore generates a single, site-specific break at a bulge in DNA in a thiol-independent reaction, involving intramolecular drug activation under general base catalysis [Kappen, L. S., & Goldberg, I. H. (1993) Biochemistry 32, 13138-13145]. As part of an effort to elucidate the three-dimensional structure of the active complex formed between the labile drug and bulged DNA, we have studied the binding of stable drug products generated in the course of the cleavage reaction with oligodeoxynucleotides containing the bulged structure. By use of fluorescence quenching, we have found that one drug product, which is also formed in the absence of bulged DNA and most closely resembles the biradical intermediate in the cleavage reaction, specifically binds bulged DNA with a Kd in the low micromolar range and competitively inhibits the cleavage reaction. Other drug products, including one formed only in the presence of bulged DNA, fail to bind to the bulged DNA. Implications of these results for the proposed mechanism of bulge-specific cleavage and for the role of the DNA bulge in generating a unique drug product are discussed.
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Affiliation(s)
- C F Yang
- Department of Biological Chemistry, Harvard Medical School, Boston, Massachusetts 02115
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Gao X, Stassinopoulos A, Rice JS, Goldberg IH. Structural basis for the sequence-specific DNA strand cleavage by the enediyne neocarzinostatin chromophore. Structure of the post-activated chromophore-DNA complex. Biochemistry 1995; 34:40-9. [PMID: 7819222 DOI: 10.1021/bi00001a006] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Neocarzinostatin chromophore (NCS chrom) belongs to a family of highly potent enediyne antitumor antibiotics which bind to specific DNA sequences and cause single- and/or double-strand lesions. NCS chrom-DNA complexes have eluded structural studies since the native form of the drug is extremely labile in aqueous conditions. We report the three-dimensional structure of the stable glutathione post-activated NCS chrom (NCSi-glu)-DNA complex [NCSi-glu-d(GGAGCGC).d(GCGCTCC)] using NMR and distance geometry-molecular dynamics simulation methods. NCSi-glu interacts with the GCTC tetranucleotide on one strand and with the AGC trinucleotide on the other strand through the unique intercalation at the 5'-CT/5'-AG step and minor groove binding. The DNA-drug complex exhibits an extended, unwound V-shaped intercalation site and wider and shallower grooves than the free DNA duplex. The structure of the complex manifests specific van der Waals interactions and H-bond formation between the carbohydrate moiety and a specific DNA sugar/phosphate. Prominent among those are the contacts of the NCSi-glu residues with the functional groups in the minor groove that are characteristic of individual DNA bases. These results provide a structural model for understanding the sequence specificity of the single- and double-strand cleavage at the AGC and related sites by the enediyne NCS chrom.
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Affiliation(s)
- X Gao
- Department of Chemistry, University of Houston, Texas 77204-5641
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Tsiourvas D, Tsartolia E, Stassinopoulos A, Barrell M, Bontemps J. A new approach to reclaimed PET utilization—blends of recycled pet suitable for extrusion blow-molding technology. Adv Polym Technol 1995. [DOI: 10.1002/adv.1995.060140306] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Chu YH, Lees WJ, Stassinopoulos A, Walsh CT. Using affinity capillary electrophoresis to determine binding stoichiometries of protein-ligand interactions. Biochemistry 1994; 33:10616-21. [PMID: 8075061 DOI: 10.1021/bi00201a007] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have developed a new method utilizing affinity capillary electrophoresis (ACE) for the determination of binding stoichiometries in biochemical systems. Using the same concentration of a ligand in the sample and the electrophoresis buffer, the appearance of an inverted peak corresponding to the free ligand in the resulting electropherogram provides a criterion of binding of a ligand to its receptor protein. For both low (fast off rates) and high (slow off rates) affinity systems, analysis of the integration of free ligand peak in electropherograms as a function of the total concentration of a ligand in samples at constant concentration of receptor protein yields the binding stoichiometry of the ligand to the protein. Applications of this technique to studies of (i) the inhibition of carbonic anhydrases (CA, EC 4.2.1.1, from human and bovine erythrocytes) by 4-alkylbenzenesulfonamide 1, (ii) the interaction of a monoclonal antibody to human serum albumin (anti-HSA) with its antigen HSA, and (iii) the binding of streptavidin (from Streptomyces avidinii) to biotin derivatives (monobiotinylated oligodeoxyribonucleotide 2, fluorescein biotin, or Lucifer Yellow biotin) yield stoichiometries of 1:1, 1:2, and 1:4, respectively. For multivalent, tight-binding systems, this ACE method can readily separate stable intermediate species. This method is generally applicable to both tight- and weak-binding systems, requires only nanograms of proteins and ligands, involves no radioactive materials, and does not require changes in electrophoretic mobilities of receptor proteins upon binding with ligands. It thereby provides a rapid, sensitive, and convenient method for measuring binding stoichiometries of ligands to proteins.
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Affiliation(s)
- Y H Chu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115
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Hensens OD, Chin DH, Stassinopoulos A, Zink DL, Kappen LS, Goldberg IH. Spontaneous generation of a biradical species of neocarzinostatin chromophore: role in DNA bulge-specific cleavage. Proc Natl Acad Sci U S A 1994; 91:4534-8. [PMID: 8183944 PMCID: PMC43820 DOI: 10.1073/pnas.91.10.4534] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Detailed structure determination of the major and minor base-catalyzed degradation products of the chromophore of the enediyne anticancer antibiotic neocarzinostatin in the absence of DNA demonstrates that the enolate Michael addition reaction leading to a spirolactone cumulene intermediate is a spontaneous, stereoselective process. The implications of these findings for the mechanism of the thiol-independent, site-specific cleavage by the so-generated radical species of the drug at a DNA bulge are described.
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Affiliation(s)
- O D Hensens
- Natural Products Chemistry Department, Merck Research Laboratories, Rahway, NJ 07065
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Harvey RF, Schullinger MB, Stassinopoulos A, Winkle E. Dreaming during scientific papers: effects of added extrinsic material. Br Med J (Clin Res Ed) 1983; 287:1916-9. [PMID: 6197133 PMCID: PMC1550176 DOI: 10.1136/bmj.287.6409.1916] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
During a series of presentations of scientific papers 40.6% of 276 subjects reported dreaming, but only 18.1% actually fell asleep. The frequency of dreaming was significantly increased by the addition of either "very boring" or "very interesting" slides to the usual ones, but not by "neutral" slides. The recall of lecture content and the proportion of audience asleep were (surprisingly) not greatly affected by the addition of extraneous slides of any sort. On the other hand, adding "very interesting" slides greatly increases audience enjoyment.
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